There is a growing demand for higher mounting density of semiconductor chips as electronic devices become more compact and higher performing. In response to this requirement, investigations have been carried out into chip-on-chip (CoC) semiconductor devices in which a plurality of semiconductor chips having through-electrodes are mounted.
Patent Document 1 (JP 2010-251347 A) indicates that a plurality of semiconductor chips which are connected to through-electrodes and have bump electrodes projecting from a substrate surface are mounted (flip-chip stacked) in such a way that the bump electrodes of the semiconductor chips above and below are connected, and the space between semiconductor chips is filled with an underfill, which is a sealing resin, in order to form a chip stack, after which the chip stack is fixed on a wiring board.